1. Field of the Invention
The present invention relates generally to the field of gas sensors, and more particularly to a method and device for measuring concentration and rate of change of concentration of a gas having ability to act as crystal etchant, such as hydrofluoric acid (HF) or deuterium fluoric acid (DF) gas.
2. Description of the Related Prior Art
Chemical lasers, employable in electronic warfare systems, use hydrofluoric acid (HF) or deuterium fluoric acid (DF) gas. To properly diagnose laser operation and to prevent damage to optical elements, it is desirable to be able to determine the concentration and rate of change of the HF or DF gas at several locations in the laser resonator beam path. Therefore, the device should be small and inexpensive so that multiple units may be placed in the same chamber or laser resonator beam path. Presently, there are no such devices available.
The appropriate measuring device should behave as a dosimeter and be able to measure the presence and rate of change of ground-state HF or DF gas in the laser resonator beam path. The HF or DF sensor should further be able to discriminate against other chemical species present in the same chamber. Moreover, since the laser resonator beam path is a very inaccessible and hostile environment, the device should be sturdy and inexpensive, to justify replacement cost. Further, the device should be applicable to other industries which use HF or DF gas, such as semiconductor and oil-refining industries.
Therefore, there is a need for a simple, inexpensive, easily calibratible, efficient and highly sensitive HF or DF sensor, which can be manufactured at high operating margins, does not require a specialized, complicated fabrication process, and which can be used in different industries for measuring HF or DF concentration and rate of change.